Variance Problem

[JOHNY CA$H]

Hey guys, this type of math is a bit foreign to me, so I was hoping you could help me out. I don't need an exact figure, just a rough estimation. How often should this scenario occur in a year? Ten years? Over a 40 yr career? What is the rough probability of it occurring?

Assume a full time professional online NL (200-400) player. Plays 25-30 hrs a week, 5 tables, and averages 5BB per hour per table (25BB per hr), or 1/4 stack per hour. How often should he:

1) Experience a 20 Buy-in downswing?

and 2) Experience two 20 buy in downswings within the span of 4 months? (Is this something he'll see every few years? Every ten? Once in a lifetime?)

Thanks in advance, I'd love to hear anyone's thoughts.

[themandude]

often if you are playing right

[JOHNY CA$H]

A rough definition of "often"? Say, a couple times a year? Every few months? Also, are you addressing #1 or #2?

[Paxinor]

i think this answers your question pretty good:

http://forumserver.twoplustwo.com/showfl...ue#Post12274178

[JOHNY CA$H]

Yeah man, that's what I was looking for and more.

Thanks, Dude!

[Eighties21Playa]

A quick approximation of Paxinor's thread is to figure, in BB, the downswing ur interested (2000), divide by STDDEV/1000 (147BB), and square the result, which will approximate k number of hands. For example, a 20+ downswing should be expected (95% confidence) every (2000/147)Sq.* k # of hands or 13.605sq k hands = approx 185k hands. Therefore, can expect 10+ downturn every 46k, 15+ every 104k and 20+ every 185k or about 2 times a year at your rate of play.
I dont know how to answer your question # 2) since it seems like it would be highly dependent on how many hands it took to suffer the first 20+ downturn. By my approximation method, one could expect a 40+ downturn every 740,000 hands (about 1 time every 2 years at your rate of play). In fact, I just suffered a 40.62BB downturn over 128k hands - so it happens!!!! And, believe me, its no fun.